/Engine/Plugins/Experimental/Animation/ContextualAnimation/Source/ContextualAnimationEditor/Public/SContextualAnimViewport.h
Implement this to add a viewport toolbar to the inside top of the viewport.
virtual [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SWidget](API\Runtime\SlateCore\Widgets\SWidget) > MakeViewportToolbar()